1. Field of the Invention
The present invention relates to a fabrication method for a semiconductor device for conducting heat treatment on a semiconductor device using a high-intensity light source, and the semiconductor device subjected thereto.
2. Description of the Related Art
Improvement in performance of a large-scale integration (LSI) semiconductor device, is achieved by increasing the scale of integration. In other words, LSI performance may be improved through miniaturization of devices configuring the semiconductor device. As a result, the LSI is increased to a larger scale, and the devices are miniaturized. In addition, for device miniaturization, a shallow pn junction should be formed at a shallow location approximately 20 nm or less from the surface of the semiconductor substrate. However, formation of a shallower pn junction concurrent with the miniaturization of devices is difficult.
A shallow impurity diffused region must be formed so as to form the shallow pn junction. As a method of forming the shallow impurity diffused region, to begin with, impurity ions with low acceleration energy are implanted in the semiconductor substrate, and the semiconductor substrate is then subjected to a heat treatment. However, with ion implantation of a p-type dopant of boron (B), an n-type dopant of phosphorous (P), and arsenic (As), as impurities, since there is a large diffusion coefficient in the silicon (Si) of the semiconductor substrate, the impurities are diffused inwardly to and outwardly from the semiconductor substrate during rapid thermal annealing (RTA). The RTA is conducted by a halogen lamp. Shallow impurity diffused regions containing a concentrated impurity can not be formed in the semiconductor substrate. On the other hand, the concentrated impurity is not activated if the heat treatment temperature in the RTA processing is decreased so as to control the impurity diffusion. As such, it is difficult to form a shallow impurity diffused region with a low resistance in the semiconductor substrate in which a concentrated impurity can be activated.
Techniques are known for forming a light absorbing film on the surface of an interlayer insulator film. Since the light absorbing film formed on the surface of the interlayer insulator film generates heat, while the semiconductor substrate itself does not generate heat, it is difficult to effectively and instantaneously heat up the semiconductor substrate.